AS IS WELL ESTABLISHED BY SCIENCE, there are two types of people in the world. There have only ever been two types. Two types alone. Amen.

Any effort to define and sort people into a third group is futile. A fourth? Abomination!

People love the binary and in fact will self-sort.

You’re either built for comfort or built for speed. You declare yourself a lover not a fighter.

You recognize the universal duality as you go about your daily life: There are those who signal and those who blithely change lanes. Those who listen and those who merely wait their turn to talk.

Cat people. Dog people. Wallflowers and dancers. Math people and the rest of us.

Don’t mess with the order of the universe. Coke or Pepsi, man. Make your choice! Commit!

It’s been true since Noah built the Ark. Two by two, dude. Two by two.

But the wise guys at Personality and Individual Differences just couldn’t leave it alone. They just had to tinker.

Guess which of these two groups they fall into? Those who make things simple and those who make things complicated.

And the result of their meddling? The title of their research tells it all: “How many diurnal types are there? A search for two further ‘bird species.’”

First of all — diurnal? Diurnal?! That in itself is a tipoff. Who says “diurnal”? These aren’t red-blooded American lab geeks.

You’re not a “diurnal” type! You’re either an early bird or a night owl. Period.

But evidently, if your family names are Putilov, Donskaya and Verevkin, you just had to investigate. You had to fiddle with the American way of life.

Sure, Mr. Putin’s emissaries start with larks (early birds) and (night) owls, like normal people. But they immediately get into unnecessary subtleties. What does it matter if you don’t fit the pigeon hole?

Because you do fit it!

Do not attempt to resist your label. You lark you. You owl.

Admit it. You’re in one of two sleepover camps: 1) You prefer to get up early and prance around cheerily as though you are something special. And so you go to sleep early because even you, in all your insane optimism, cannot sustain that level of irritating merriment past dark. Thereby, you are an early bird — a lark.

Or, 2) You prefer to rise according to the prophecy — when the midmorning sun is on your face and the cat is desperate for nourishment. You go about your business like a sensible human being and get your news of the world from Jon Stewart and Stephen Colbert, thereby demonstrating your night owlishness.

Don’t fight it! Resistance is futile. And rough on the feathers.

But here we go: Thanks to the Russkies we now have two more types of sleep/wake patterns to somehow cope with. They identified a third group of extremely annoying people who feel high energy in the morning as well as at night.

Where do these people fit in? What are we normal dichotomous folks supposed to do with Diurnal Group #3? They probably put ketchup on their hotdogs for God’s sake.

I’ll bet they unwrap packages by slipping their fingers along the edge of the seam, loosening the tape, just so, saving the paper and ribbons for reuse. I really hate these people. Really, I do.

What shall we call these giddily energetic folks? Why, hummingbirds of course! They’re probably high on sugar water.

And then there’s the fourth group — those who feel lethargic all day. These guys make us night owls look bad.

If we nap during in the afternoon to make up some REM time, the logic holds; but Group 4 sullies that fine institution.

There, there. Poor weary you. You’re too worn out to eat the crust of your pizza. You don’t have the strength to sort your Skittles.

Look, just because you lie about heaving heavy sighs, back of your hand to your forehead all day, doesn’t mean you deserve your own avian appellation.

But it’s too late now. The damage is done. Patterns detected and documented. The only thing remaining is the moniker. And the Russians don’t disappoint.

What better name to call such a ringer? Number 4 in a two-category world?

Turkey!

Carolyn Plath, M.Ed., is a Benicia resident and retired high school principal. Read her blog at thinkdreamplay.blogspot.com.